igntion switch removal HELP!!

i have a 1996 chevy astro van and it wont start. the problem that i have everytime i try to start it blows the fuse in the ignition A i tried to disconnect the starter until it blew the same fuse over and over again. i disconnected the park/neutral switch and it doesnt blow the fuse when i do that. i installed a new park/neutral switch but it doesnt work. i also changed the starter relay and the same problem. now i want to try to change the ignition electronic box switch and id like to know how to remove the air bag or if you know what caused this problem. PLZ HELP!!!!!!im going crazy trying to fix this van!